Headlight-lens.



D. FOSTER.

HEADLIGHT LENS.

APPLICATION FILED SEPT. 1 1. 19:1.

1,261,375., Patented Apr. 2, 1918.

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[Au a WITNESSES- 37 INVENTOR [3mm Fig. 3 jwmA dfl 5 6 fi M/wz'p BYDONOVAN FOSTER, OF MOSCOW, IDAHO.

. HEADLIGHT-LENS.

Specification of Letters Patent.

Patented Apr. 2, 1913.

Application filed September 11, 1917. Serial No. 190,760.

To all whom it may concern:

Be it known that I. DONOVAN FOSTER, a citizen of the United States,residing at Moscow, in the county of Latah and State of Idaho, haveinvented certain new and useful Improvements in Headlight-Lenses, ofwhich the following is a specification.

The object of this invention is the per-.

fecting of headlight lenses whereby the light rays are directed toeffectually illuminate the ground in advance of the vehicle and preventthe direct rays from the light being seen by a person facing the lamp.

The invention consists in the novel construction, adaptation andarrangement of parts in a lens as will be hereinafter described andclaimed.

In the accompanying drawings, Figure 1 is a vertical sectional view of aheadlight reflector with a lens embodying my improvements appliedthereto. Fig. 2 ,is a horizontal sectional view of the same. Fig. 3 is adetail horizontal sectional view of the improved lens to illustrate theregulation thereby of light rays from a reflector such as represented inthe preceding views. Fig. 4 is a front elevational view of the lensshown in Figs. 1 and 2.

Referring to the drawings, the reference numeral 5 designates aparabolic reflector such as usually employed in headlights and 6represents a lens embodying the various features of the presentinvention.

The front of the lens is formed with a plurality of superposed prisms A,B, C, etc., having front faces 7 7 etc., which incline forwardly fromthe upper edges of each to the bottoms 8 8 etc., of the respectiveprisms, said bottoms being inclined to be parallel, or nearly so, withthe reflected rays as bentdownwardly by the respective prisms. In thefront face of the prism B, which is located directly in front of light,indicated by F (Figs. 1 and 2), is provided a recess of a substantiallytriangular shape in front elevation (Fig. 4) and having two triangularlyshaped plane surfaces 9 which are disposed in angular relations withrespect to each other and to a vertical line 10 located in a plane,indicated by broken lines A Fig. 2, passing through the light or innerfocus F.

By thus arranging the surfaces 9 the direct rays from the light are bentoutwardly as represented by a a m Fig. 2 to render the lightindiscernible to a person in front of the lamp. The recess surfaces 9are furthermore arranged to slope somewhat for- Wardly from their upperedges 11 toward the bottom edges 12 thereby directing the light raysdownwardly similarly to the aforesaid prisms.

The lens face opposite to that provided with prisms is corrugated by theprovision of vertically disposed ridges and concavities, formed andarranged tangentially to furnish a sinusoidal surface comprisingalternating convex and concave portions 13 and 14, respectively. Therays from the parabolic reflector are directed therefrom substantiallyrectangularly to the lens as indicated by darts b, b in Fig. 3, thosepassing through the convex portions 13. being caused to converge, as atc, to focal lines whence the rays diverge as indicated by d.

The reflected rays passing through the concave portions 14 are therebycaused to diverge, as at e, from axial lines f and be diffused among therays 05 in advance of a plane, as y-y for example, to produce anilluminated field with an absence of spots or unlighted areas.

The forming of the lens with a face having a curve-ofsines surfacecauses the light rays tobe not only more evenly distributed but alsospreads them horizontally without diminishing their illuminating value.

What I claim, is

1. A substantially circular plate headlight lens having a prismaticfront face formed to refract downwardly all rays passing through thelens, and a plurality of vertical connected plus and minus cylindricallenses forming a uniform sinusoidal rear face for said lens, said lenseseach being formed to include not more than substantially one-third ofacomplete cylinder to thereby effect intersection and diflusion of allrays emitted from the lens without reflection thereof.

2. A substantially circular plate headlight lens having a plurality ofhorizontal transverse prisms on its front face formed to refractdownwardly all rays passing through the lens, and a plurality ofvertical connected alternating plus and minus cylindrical lenses forminga uniform sinusoidal rear face for said lens, said lenses each beingformed to include not more thansubstantially one third of a complete cylnder to thereby effect intersection and diffusion of all rays emittedfrom the lens without reflection thereof.

3. A substantially circular plate headlight lens having a plurality ofhorizontal transverse prisms on its front face formed to refractdownwardly all rays passing through the lens, a plurality of verticalconnected alternating plus and minus cylindrical lenses forming auniform sinusoidal rear face for said lens, said lenses each beingformed to include not more than substantially one third of a completecylinder to thereby efi'ect intersection and difiusion of all raysemitted from the lens Without -reflection thereof, and a recess providedcentrally in said front face adapted to refract light, passing throughthe lens directly from a light source, laterally Without diffusion.

Signed at Seattle, Washington, this 5th day of September, 1917.

DONOVAN FOSTER. Witnesses:

PIERRE BARNES, ANNA SCHROEDER.

